Powder inhalator

ABSTRACT

A powder inhaler includes a housing with a reservoir for a powdery drug and a gas passage duct extending through the housing. A metering device is provided for supplying metered quantities of the powdery drug from the reservoir to the gas passage duct. A secondary flow separating chamber is arranged in communication with the gas passage duct.

FIELD OF THE INVENTION

The invention relates to a powder inhaler including a reservoir forpowdery drugs, a metering device and a gas passage duct.

PRIOR ART

Numerous powder inhalers are known. A problem in the known powderinhalers is the insufficient protection against air humidity and thedivision, which is made difficult as a result of the latter, of apowdery drug conglomerate under the effect of flow of a gas or gasmixture into small particles, whose size must be within appropriatelimits so that they can pass into the sites of action intended for themin the human respiratory tract. Operation of the known powder inhalersis complicated, as a result of which use by handicapped people and usein situations of stress are not guaranteed. Additionally, an indicationof the remaining quantity of the drug which can still be applied wouldbe desirable. In known powder inhalers, there is the risk of dosefluctuations. Furthermore, in terms of their constructional size, knownpowder inhalers exceed pocket size and thus comply only to a limitedextent with appropriate practical use.

DESCRIPTION OF THE INVENTION

One object of the invention is seen in achieving an application ofpowdery drugs by inhalation with the greatest possible certainty ofapplication as the result of simple, invariable sequence of operationand precise metering by pushing the button only once. Moreover, it is tobe possible for the application, that is to say the inhalation, to takeplace independently of the state of the button triggering the metering,that is to say it is to be possible for the button to remain pressedduring the application or to be released previously.

A further aim of the invention consists in designing the exchange of thedrug reservoir to be simple and inevitable and in not permittingoperation errors. Additionally, the drug reservoir is to beimplementable with the least amount of material and with simple contoursin order to achieve cost-effect refilling with drugs, a low materialweight relative to the volume to be received and a small amount ofpackaging. In addition to precise metering of the drug, the drug powderis to be separated to the largest possible extent during theapplication. Additionally, the powder applicator is to be as easy aspossible to clean, for example by a jet of water.

These objects are achieved by powder inhalers including a reservoir forpowdery drugs, a metering device and a gas passage duct.

It has been shown that an improved separation of powder agglomerates ofactive substances can be achieved by a secondary flow separatingchamber. This leads to a greater proportion of the drug being depositednot in the mouth and throat area, but at the desired destination in thelung.

The subject of the invention is therefore constituted by powderinhalers, in which the gas passage duct communicates with a secondaryflow separating chamber.

A further subject of the invention is constituted by powder inhalers,whose metering device consists of a metering drum, which can be rotatedabout a camshaft, having rams which are displaceable perpendicular tothe axis of rotation through the camshaft in openings in the wall of themetering drum which is rotated further through the angle between tworams in each case when the push-button is actuated.

A further subject of the invention is constituted by powder inhalers,whose reservoir is mounted in a guide bush and is pressed by acompression spring against the metering drum in an interlocking manner.

A further subject of the invention is constituted by powder inhalers, inwhich a movable substrate plunger is provided in the reservoir, whichsubstrate plunger is loaded by a substrate spring as soon as the powderinhaler is activated by a push-button.

BRIEF DESCRIPTION OF THE DRAWING

The single FIGURE of the drawing is a schematic sectional view of thepowder inhaler according to the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

A push-button 1 is integrated in the housing 29 of the powder inhaler.Said push-button is pushed upwards by the compression spring 8 into itsposition of rest. The metering drum 10 is mounted rotatably in thehinged rear part 13 of the housing. Said metering drum has the shape ofa thick-walled cylinder with openings through the cylinder wall. Movablerams 11, corresponding to the shape of the cross section of the opening,are mounted in these openings in such a way that they constantly bearagainst a camshaft 9 and thus expose a volume 15 on the surface of themetering drum 10, which volume depends on the respective position of theram 11 relative to the camshaft 9. The guide bush 2 for the reservoir 3is pressed with its seal 16 by the compression spring 5 against themetering drum 10 in an interlocking manner. The guide bush 2 for thereservoir 3 is sealed off in relation to the housing by the folding seal4. The guide bush 2 for the reservoir 3 can be circular, oval orpolygonal in cross-section and receives the reservoir 3 which cancorrespondingly likewise be circular, oval or polygonal incross-section. The reservoir 3 is constantly pressed by the compressionspring 6 against the metering drum 10 in an interlocking manner. Uponactuation of the push-button 1 and interruption associated therewith, ofthe magnetic flow from the magnet 28 via the iron magnetic conductorcoupling 27 on to the coupling bar 26, the substrate spring 20 pressesthe substrate plunger 18 with slight spring force against the powderydrug 17. An indication of the quantity remaining is possible through atransparent cutout 7 by appropriate marking of the coupling bar 26.Moreover, complete filling of the volume 15 on the surface of themetering drum 10 is thereby achieved. By converting the lifting movementto a rotary movement, the actuation of the push-button 1 leads to arotation of the metering drum 10 through the angle between two adjacentrams 11. If there are four rams 11, the actuation of the push-button 1leads to a quarter-rotation of the metering drum 10. At the same time,the guide bush 2 for the reservoir 3 is moved away from the meteringdrum 10 by the push-button 1 in order to release the seal 16 between themetering drum 10 and the guide bush 2 for the reservoir 3. At the sametime, the magnet 28 is released from the magnetic conductor coupling 27and thus cancels the magnetic fixing of the coupling bar 26. The springforce of the substrate spring 20 acts on the substrate plunger 18 onlyduring this period of the push-button 1 being pressed. The volume 15produced on the surface of the metering drum 10--caused by the positionof the camshaft 9 relative to the ram 11--is filled with the powderydrug 17 which is ejected again by the ram 11 near to the end of therotary movement of the metering drum 10 and can be scraped off by ascraper 14. On return of the push-button 1 into its position of rest,the guide bush 2 for the reservoir 3 is again pressed with its seal 16against the metering drum 10 by the compression spring 5. The reservoir3 constantly remains pressed against the metering drum 10 by thecompression spring 6 during the entire removal operation and thusremains closed even during removal. The entry of air 12 in the rear part13 of the housing takes place by inspiration at the mouthpiece 31 and,due to the flow pressure, carries along the drug scraped off at thescraper 14. Due to the shaping of the flow duct 19, a main flow 21 ofair and a secondary flow 25 of air are produced. Heavy drugconglomerates 22, which have not yet been atomized to an appropriatesize, cannot follow the main flow 21 of air due to their weight and areswirled in the secondary flow separating chamber 24. Agglomerates arecarried from the path and remain in the atomizing region 23 until theyhave been atomized to the extent that they can be carried along by theflow pressure. The flow pressure is determined by the width of the flowduct 19 and can thus be adjusted to different sizes. Due to the greatwidth and thus low flow pressure at the entry of the secondary flowseparating chamber 24, the drug conglomerates 22 are reliably flung fromthe path and can only be carried along by the increased flow pressure inthe case of narrow width of the flow duct above the secondary flowseparating chamber 24, if they are light enough to pass into its suctionregion. They then pass through the filter 30 and arrive in the regionscorresponding to their size in the human respiratory tract.

I claim:
 1. A powder inhaler comprising a housing having an axis, the housing defining a reservoir for a powdery drug and a gas passage duct extending essentially in axial direction through the housing, the housing comprising a first opening of the gas passage duct for taking air into the gas passage duct and a second opening of the gas passage duct for inhaling air from the gas passage duct and for producing a primary air flow in the gas passage duct in a flow direction, further comprising a metering device for supplying metered quantities of the powdery drug from the reservoir into the gas passage duct, the gas passage duct having at a location between the first and second openings a bend portion in which bend portion the gas passage duct is curved from the axial direction to an upward direction transversely of the axial direction, the gas passage duct further having an upwardly directed gas passage duct portion following the bend portion in flow direction, and an essentially circular secondary flow separating chamber arranged in communication with an essentially tangentially to the bend portion of the gas passage duct, such that a lighter fraction of the powdery drug is conducted by the primary air flow through the bend portion and the upwardly directed portion of the gas passage duct and a heavier fraction of the powdery drug is conducted into and swirled within the secondary flow separating chamber.
 2. The powder inhaler according to claim 1, the metering device comprising a cam shaft having an axis of rotation, a metering drum rotatably mounted on the cam shaft, the metering drum having a wall defining openings, rams mounted in the openings so as to be displaceable by means of the cam shaft in a direction extending perpendicularly to the axis of rotation of the cam shaft, an angle being defined between adjacent openings, and a push-button in operative connection with the metering drum for rotating the metering drum by the angle between two openings.
 3. The powder inhaler according to claim 2, wherein the reservoir is mounted in a guide bush, further comprising a compression spring for pressing the reservoir against the metering drum in an interlocking manner.
 4. The powder inhaler according to claim 3, further comprising a movable substrate plunger mounted in the reservoir, a substrate spring connected to the substrate plunger, and means for loading the substrate plunger by the substrate spring when the push-button is activated. 